King crab

King crabs, also called stone crabs, are a superfamily of crab-like decapod crustaceans chiefly found in cold seas. Because of their large size and the taste of their meat, many species are widely caught and sold as food, the most common being the red king crab, Paralithodes camtschaticus.

King crabs are generally thought to be derived from hermit crab-like ancestors, which may explain the asymmetry still found in the adult forms. Although some doubt still exists about this theory, king crabs are the most widely quoted example of carcinisation among the Decapoda. The evidence for this explanation comes from the asymmetry of the king crab's abdomen, which is thought to reflect the asymmetry of hermit crabs, which must fit into a spiral shell. Although formerly classified among the hermit crabs in the superfamily Paguroidea, king crabs are now placed in a separate superfamily, Lithodoidea.^[1]

Contents 1 Species 1.1 Glyptolithodes 1.2 Lithodes 1.2.1 Lithodes aequispinus 1.2.2 Lithodes couesi 1.2.3 Lithodes maja 1.3 Neolithodes 1.3.1 Neolithodes yaldwini 1.4 Paralithodes 1.4.1 Paralithodes camtschaticus 1.4.2 Paralithodes platypus 2 See also 3 References 4 External links

Species

Around 121 species are known, in 10 genera:^[2]

Glyptolithodes

Glyptolithodes is found chiefly in the Southern Hemisphere, but extending as far north as California, although all its closest relatives live in the Northern Hemisphere. Its single species, G. cristatipes was originally placed in the genus Rhinolithodes.

Lithodes

Lithodes aequispinus

The golden king crab, Lithodes aequispinus, is caught in the Aleutian Chain off the coast of Alaska. The golden king crab is significantly smaller than the red and blue king crabs, averaging 5–8 pounds (2.3–3.6 kg).^[3] It tastes similar to the red and blue king crabs, though perhaps somewhat sweeter. They are considerably cheaper due to their appearance and size.

Significant populations occur in pockets in the waters off the Pribilof and Shumagin Islands, Shelikof Strait, Prince William Sound and at least as far south as lower Chatham Strait in the south-east, where a regular commercial fishery occurs annually. It should be noted they occur in deeper water than the red king crab, often in depths exceeding 300 fathoms (1,800 ft; 550 m). Juvenile golden king crabs are cryptic and rely on structure-forming sessile invertebrates growing on the sea floor – such as corals, sponges and sea-whips – to provide habitat. These sessile invertebrates are slow-growing and they are at risk in certain areas where commercial fishing by bottom trawling has been common practice. For this reason, large tracts of the sea floor along the Aleutian Island chain have been protected from bottom trawling under the Magnuson-Stevens Fishery Conservation and Management Act.

Lithodes couesi

The scarlet king crab, Lithodes couesi, is not often fished due to its small size and insufficient population to support commercial harvesting.

Lithodes maja

Lithodes maja occurs in the North Atlantic, including Northern Europe and Canada's east coast. It is not abundant enough to support commercial fishery, and is becoming rare in some areas.

Neolithodes

Neolithodes yaldwini

In 2011, the scientists have found Neolythodes yaldwini on the edge of Antartica, probably as a result of global warming, with major impacts on sediment texture, bioturbation and local faunal diversity.^[4][5]

Paralithodes

Red (P. camtschaticus) and blue (P. platypus) king crabs are some of the most important fisheries in Alaska, however populations have fluctuated in the past 25 years and some areas are currently closed due to overfishing. The two species are similar in size, shape and life history.^[6][7][8] Habitat is the main factor separating the range of blue and red king crabs in the Bering Sea.^[9] Red king crabs prefer shallow, muddy or sandy habitats in Bristol Bay and Norton Sound,^[9][10] while blue king crabs prefer the deeper areas made up of cobble, gravel and rock that occur around the Pribilof, St. Matthew,^[11][12] St. Lawrence and the Diomede Islands.

Red king crabs have an 11-month brood cycle in their first reproductive year and a 12 month cycle thereafter.^[8] Both red and blue king crabs have planktotrophic larvae that undergo 4 zoeal stages in the water column and a non-feeding, glaucothoe stage which is an intermediate stage which seeks appropriate habitat on the sea floor.

Paralithodes camtschaticus

The red king crab, Paralithodes camtschaticus, is a very large species, sometimes reaching a carapace width of 11 in (28 cm) and a leg span of 6 ft (1.8 m). Its natural range is the Bering Sea, between the Aleutian Islands and St. Lawrence Island. It can now also be found in the Barents Sea and the European Arctic, where it was intentionally introduced and is now becoming a pest.^[13][14]

Paralithodes platypus

The blue king crab, Paralithodes platypus, lives near St. Matthew Island, the Pribilof Islands, and the Diomede Islands, Alaska, and there are populations along the coasts of Japan and Russia.^[12] Blue king crabs from the Pribilof Islands are the largest of all the king crabs, sometimes exceeding 18 lb (8 kg) in weight.^[15]

See also

• Alaskan king crab fishing
• Deadliest Catch

References

External links

• Media related to [//commons.wikimedia.org/wiki/Category:Lithodidae Lithodidae] at Wikimedia Commons
• Data related to Lithodidae at Wikispecies